US5764447A - High reluctance magnetic head - Google Patents

High reluctance magnetic head Download PDF

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Publication number
US5764447A
US5764447A US08/794,910 US79491097A US5764447A US 5764447 A US5764447 A US 5764447A US 79491097 A US79491097 A US 79491097A US 5764447 A US5764447 A US 5764447A
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US
United States
Prior art keywords
magnetic
amagnetic
layer
magnetic head
concentrators
Prior art date
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Expired - Fee Related
Application number
US08/794,910
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English (en)
Inventor
Jean-Pierre Lazzari
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Silmag
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Silmag
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Assigned to SILMAG reassignment SILMAG ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: LAZZARI, JEAN-PIERRE
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
    • G11B5/3967—Composite structural arrangements of transducers, e.g. inductive write and magnetoresistive read

Definitions

  • the present invention relates to a high reluctance magnetic head. It has an application in information recording.
  • the invention essentially applies to so-called thin film, horizontal heads.
  • a head is shown in the attached.
  • FIG. 1 it is possible to see in section a head having a semiconductor substrate 10, e.g., of silicon, in which has been etched a recess 12. Within said recess has been electrolytically formed a rear magnetic layer 14 and this has been extended by two vertical posts 16 1 , 16 2 .
  • a coil 18 surrounds the posts and is embedded in an insulating layer 20.
  • the magnetic circuit is completed by a front magnetic piece incorporating two pole pieces 22 1 , 22 2 separated by an amagnetic spacer 24.
  • a magnetoresistant element MR is placed beneath the amagnetic spacer 24.
  • the head is moved in front of a magnetic support 30, where the information to be read or written are recorded.
  • Such a head is described in FR-A-2 645 314 (or the corresponding U.S. Pat. No. 5,225,716).
  • the current flowing in the coil 18 creates a magnetic field and consequently an induction in the magnetic circuit.
  • the field lines which spread out around the spacer induce a magnetization in the support 30.
  • magnetic information recorded in the support 30 produces a magnetic reading field and consequently an induction in the magnetic circuit and which is partly closed across the magnetoresistant element MR. This leads to a magnetization rotation in said element, which will bring about a variation in its resistance.
  • FR-A-2 657 189 recommends opening the magnetic circuit in such a way that the aforementioned path (a) is interrupted, so that preference is then given to path (b).
  • said document recommends eliminating the magnetic posts 16 1 , 16 2 or even eliminating the rear magnetic piece 14.
  • the writing signal is greatly weakened or attenuated by such upheavals to the magnetic circuit.
  • EP-A-475 397 also recommends opening the magnetic circuit, but in a different way. It recommends producing a gap in the rear magnetic piece, or two auxiliary gaps in the posts, while adding a second magnetic circuit used in reading and able to reinforce the flux directed towards the magnetoresistant element. This solution is relatively complex and makes the production process for the head both long and costly.
  • the object of the present invention is to obviate these disadvantages. It recommends increasing the reluctance of the magnetic circuit, but in a simpler way.
  • the invention is firstly applicable to heads having, in addition to the means shown in FIG. 1, two flux concentrators located above the two posts and magnetically coupled to the two pole pieces.
  • the invention recommends separating said concentrators from the pole pieces by an amagnetic layer.
  • Such a layer can be easily deposited during production following the formation of the concentrators.
  • the magnetic decoupling brought about in this way eliminates the numerous magnetic leaks, which disturb the operation of the prior art heads with auxiliary gaps.
  • the present invention relates to a magnetic head incorporating a magnetic circuit with two magnetic concentrators and two pole pieces separated by an amagnetic spacer and a magnetoresistant element located beneath the amagnetic spacer, said head being characterized in that the two concentrators are separated from the two pole pieces by an amagnetic layer incorporating at least one conductive layer.
  • the amagnetic layer can have a thickness between a fraction of a microns and a few microns.
  • the amagnetic layer can be constituted by an insulating layer (e.g. of silica) covered with a conductive layer (of copper, chromium, tungsten, etc.).
  • the conductive layer will serve as the electrode in an electrolytic growth stage for the pole pieces.
  • the structure is symmetrical and the reading signal is also symmetrical.
  • FIG. 1 already described, diagrammatically illustrates a thin film horizontal magnetic head.
  • FIG. 2 already described, shows the magnetic fluxes during reading.
  • FIG. 3 illustrates a first subassembly obtained after producing concentrators.
  • FIG. 4 illustrates the deposition of an amagnetic layer on the concentrators.
  • FIG. 5 shows a supplementary stage.
  • FIG. 6 illustrates the electrolytic growth operation for part of the upper magnetic piece.
  • FIG. 7 illustrates a finished magnetic head according to the invention.
  • FIGS. 3 to 6 show subassemblies obtained during the production of a magnetic head according to the invention, the finished head being illustrated in FIG. 7.
  • FIG. 3 shows a first subassembly having on a substrate 10 a rear magnetic piece 14, two posts 16 1 and 16 2 , two concentrators 19 1, 19 2 and a conductive winding 18 embedded in an insulator 20.
  • the concentrators can have a random shape, but the width of said parts towards the center of the head is smaller than level with the posts.
  • an amagnetic layer 30 which in the illustrated variant, comprises an insulating layer 32, e.g., of silica, covered with a metal layer 34, e.g., of tungsten.
  • an insulant or resin layer 36 On said assembly is then deposited (cf. FIG. 5) an insulant or resin layer 36, in which are etched two recesses 38 1 and 38 2 .
  • the process then continues with known operations, namely the formation of a magnetoresistant element, the formation of an insulating wall and the growth of pole pieces on either side of the wall.
  • the head finally obtained is shown in FIG. 7 with its two pole pieces 22 1 , 22 2 , separated by the amagnetic spacer 24 and the magnetoresistant element MR. The latter is placed beneath the spacer, either beneath the pole pieces, as illustrated, or between the latter.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Magnetic Heads (AREA)
US08/794,910 1996-03-19 1997-02-04 High reluctance magnetic head Expired - Fee Related US5764447A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9603390 1996-03-19
FR9603390A FR2746572B1 (fr) 1996-03-19 1996-03-19 Tete magnetique a forte reluctance

Publications (1)

Publication Number Publication Date
US5764447A true US5764447A (en) 1998-06-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
US08/794,910 Expired - Fee Related US5764447A (en) 1996-03-19 1997-02-04 High reluctance magnetic head

Country Status (4)

Country Link
US (1) US5764447A (de)
EP (1) EP0797188A1 (de)
JP (1) JPH1031809A (de)
FR (1) FR2746572B1 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6762910B1 (en) 1999-06-03 2004-07-13 Western Digital (Fremont), Inc. Data storage and retrieval apparatus with thin film read head having inset extra gap insulation layer and method of fabrication
US20040145827A1 (en) * 2003-01-29 2004-07-29 International Business Machines Embedded wire planar write head system and method
US6801408B1 (en) 2000-11-02 2004-10-05 Western Digital (Fremont), Inc. Data storage and retrieval apparatus with thin film read head having a planar sensor element and an extra gap and method of fabrication thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0475397A2 (de) * 1990-09-12 1992-03-18 Sony Corporation Flächenförmiger dünnschichtiger Magnetkopf
EP0651374A2 (de) * 1993-11-01 1995-05-03 Hewlett-Packard Company Planarer magnetoresistiver Kopf
US5434733A (en) * 1994-02-18 1995-07-18 Hewlett-Packard Company Planar head having separate read and write gaps
EP0669607A2 (de) * 1994-02-28 1995-08-30 Read-Rite Corporation Magnetkopfzusammenbau mit MR-Sensor
US5648884A (en) * 1994-09-13 1997-07-15 Commissariat A L'energie Atomique Magnetic head with an underlying longitudinal multilayer magnetoresistor

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0475397A2 (de) * 1990-09-12 1992-03-18 Sony Corporation Flächenförmiger dünnschichtiger Magnetkopf
US5274520A (en) * 1990-09-12 1993-12-28 Sony Corporation Thin film magnetic head
EP0651374A2 (de) * 1993-11-01 1995-05-03 Hewlett-Packard Company Planarer magnetoresistiver Kopf
US5434733A (en) * 1994-02-18 1995-07-18 Hewlett-Packard Company Planar head having separate read and write gaps
EP0669607A2 (de) * 1994-02-28 1995-08-30 Read-Rite Corporation Magnetkopfzusammenbau mit MR-Sensor
US5648884A (en) * 1994-09-13 1997-07-15 Commissariat A L'energie Atomique Magnetic head with an underlying longitudinal multilayer magnetoresistor

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6762910B1 (en) 1999-06-03 2004-07-13 Western Digital (Fremont), Inc. Data storage and retrieval apparatus with thin film read head having inset extra gap insulation layer and method of fabrication
US6801408B1 (en) 2000-11-02 2004-10-05 Western Digital (Fremont), Inc. Data storage and retrieval apparatus with thin film read head having a planar sensor element and an extra gap and method of fabrication thereof
US20040145827A1 (en) * 2003-01-29 2004-07-29 International Business Machines Embedded wire planar write head system and method
US6947256B2 (en) * 2003-01-29 2005-09-20 International Business Machines Corporation Embedded wire planar write head system and method
US20050235483A1 (en) * 2003-01-29 2005-10-27 International Business Machines Corporation Embedded wire planar write head system and method
US7322096B2 (en) * 2003-01-29 2008-01-29 International Business Machines Corporation Method for fabricating magnetic write heads

Also Published As

Publication number Publication date
JPH1031809A (ja) 1998-02-03
FR2746572B1 (fr) 1998-07-24
FR2746572A1 (fr) 1997-09-26
EP0797188A1 (de) 1997-09-24

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AS Assignment

Owner name: SILMAG, FRANCE

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:LAZZARI, JEAN-PIERRE;REEL/FRAME:008490/0953

Effective date: 19970116

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Lapsed due to failure to pay maintenance fee

Effective date: 20020609